package com.tju.eduservice;

import java.util.*;

public class TestPack {



    public static void main(String[] args) {
        HashMap<Integer, Integer> map = new HashMap<>();
        Set<Integer> integers = map.keySet();
        Collection<Integer> values = map.values();
        Set<Map.Entry<Integer, Integer>> entries = map.entrySet();

    }




}

enum SEASON  {
    SPRING,
    SUMMER;
    public static int add(){
        return 0;
    }
}
